Apparatus for enclosing a resistance wire tape between flat sections of insulating ceramic paste compound



' Mai-ch 10,. 1970 ARES'KOUG 3,499,816

APPMUHUS FOR EN S A RESISTANCE HIRE "IAP ET N FLAT SEOTIONS INSULATING CERAMIC PASTE C POU FiledJune 3, 1965 v 2 Sheets-She et 1 March 10, 1970 c. o. ARasKous 3, APPARATUS FOR ENCLOSING A RESISTANCE WIRE TAPE BETWEEN FLAT SECTIONS OF INSULATING CERAMIC PASTE COIPO D 4 Filed June 3, 1965 2 Sheets-Sheet 2 United States Patent 3,499,816 APPARATUS FOR ENCLOSIN G A RESISTANCE WIRE TAPE BETWEEN FLAT SECTIONS OF INSULATING CERAMIC PASTE COMPOUND Carl Otto Areskoug, Vimmerby, Sweden, assignor to AB Installationsmateriel, Vimmerby, Sweden, a corporation of Sweden Filed June 3, 1965, Ser. No. 461,091 Claims priority, application Sweden, June 4, 1964, 6,821/ 64 Int. Cl. B32b 31/02; B29c 15/00; B29d 7/04 US. Cl. 156-436 4 Claims ABSTRACT OF THE DISCLOSURE A ceramic insulation paste material is continuously split into two moving flat parallel sections while emerging from a nozzle, a tape of resistance wire is inserted between, and moved along with, the insulation sections. The sections are then squeezed together enclosing the resistance wire.

The present invention relates to arrangements for applying, for example, a ceramic compound about a fiat structure. It is known in prior art when manufacturing ceramic resistors to embed a tape in between two strands of a ceramic compound on which tape the resistance filament units of the resistor to be made are arranged. As a rule, the two strands are provided to be extruded, each from a separate nozzle on either side of the flat tape planar structure. However, this entails a number of drawbacks with respect to the extrusion through the nozzles of the ceramic compound, since it is extremely difficult to achieve any uniform extrusion owing, for example to varying viscosity of the ceramic compounds. The present invention has for its object to avoid the said drawbacks.

An arrangement according to the present invention is substantially characterized in that a nozzle is provided to form a strand of a ceramic compound, the compound strand close to the outlet end of the nozzle being arranged to be split into two strand halves, which are to pass on either side of the tape structure and then rolled together while enclosing the tape structure.

A further arrangement according to the invention is characterized substantially in that a nozzle is of such a shape as to form a compound strand which is substantially V-shaped, the legs of the compound strand being arranged to be compressed while enclosing a tape structure in between the said legs.

The present invention will be explained more in detail hereinafter with reference to the accompanying drawings, in which FIG. 1 is a perspective view of an embodiment according to the invention, and

FIG. 2 illustrates another embodiment in a perspective view.

The arrangement shown in FIG. 1 comprises a nozzle 50 shaping and delivering a strand of a ceramic compound. Adjacent to the orifice of the nozzle a steel wire 52 is provided, which is clamped in a U-shaped fitting 53. The said steel wire splits the compound strand 51 into two strand halves 54, 55, which are separately made to run over a first couple of rollers 56, 57, respectively. Thence the strand halves 54 and 55 each run over a couple of rollers 58, 59, respectively. A tape 3 of resistance units, as mentioned in the preamble, passes over two idlers 62, 63. From the idler 63 the tape is fed in between the two rollers 60 and 61, the tape thus lying between the two strand halves 54, 55.

The strand halves and the resistance tape will then pass in between the rolls 26, 27 to be compressed into a unitary strand 30'.

By the arrangement described hereinbefore it is warranted that the two strand halves 54 and 55 become uniform, i.e. there will arise no tendency to creasing of the one or the other strand half owing to any too rapid extrusion. Another advantage of the arrangement consists in the fact that the steel wire 52 causing the splitting up of the compound strand 51 will also bring about a roughened surface structure of the partings of the strand halves 54, 55. Such a surface structure is of advantage when rejoining the strand halves between the rolls 26, 27, since effective binding between the strand halves is thus readily achieved.

Naturally, it is possible to carry out the arrangement as described hereinbefore by applying sliding paths for the strand halves 54, 55 instead of the rollers 56 to 61 as illustrated. It is also possible to replace the steel wire 52 by a knife member in which case the side faces of the knife member may be connected to the said sliding paths.

The embodiment shown in FIG. 2 comprises a nozzle 64 of Vshape having two legs 65, 66. The nozzle delivers a strand of a ceramic compound formed in a corresponding way with two legs 67, 68. A tape 3 of resistance units 3, as shown in FIG. 1, is by means of the legs 65, 66 of the nozzle 64 fed in between the said legs and preferably in parallel with the horizontal leg 66. The resistance tape will then rest on the leg 68 of the compound leg while being fed towards the rolls 26, 27. However, it is not necessary, that the tape rests on the leg 68, but it should, however, be parallel to the same just before entering between the rolls 26, 27. The leg 67 of the compound strand will then come into touch with the cylindrical face 29 of the roll 27 and be rolled down towards the leg 68 and compressed between the said rolls into a common material strand 30. As will be apparent, two uniform strand halves of a ceramic compound are achieved in a very simple manner, it being easy to roll together the same, while they do not require any directed guiding means to make them land one right on top of the other to be rolled together, as the legs 67, 68 are all the time interconnected at their base portion.

What is claimed is:

1. An apparatus for enclosing a plurality of planar resistance wire convolutions with an insulating ceramic paste compound jacket comprising: extruding means including a container for the compound having a single nozzle opening; means located near and in the path of the nozzle for uniformity dividing the compound into two continuous fiat portions having rough opposing surfaces and diverging from one another in a Vshaped configuration; means located downstream of the dividing means for guiding the two portions along spaced apart longitudinally and laterally parallel paths; means for continuously conveying the planar wire convolutions along a path both longitudinally and laterally parallel to, and in between of, the compound portions; rejoining means located downstream of the guiding and conveying means for applying pressure perpendicular to both the longitudinal and lateral directions of the compound portions and the planar wire convolutions; whereby the compound will be extruded, divided at a uniform rate without creasing the two portions, then rejoined together completely around the wire convolutions.

2. An apparatus as in claim 1 wherein the guiding means comprise rollers.

3. An apparatus as in claim 1 wherein the dividing means comprises a wire.

4. A device as in any of the claims 1, 2 or 3 wherein the conveying means comprises first and second cylindrical rollers located between said portions with said first 3 4 roller nearer said dividing means and said second roller 2,744,041 5/1956 Balchen 156-244 XR nearer said rejoining means, each of said rollers having 3,082,292 3/1963 Gore 264175XR its axis of rotation perpendicular to each other and to the 3,068,135 12/1962 Bower 156436 XR longitudinal direction with a tangential direction of the 1,846,325 2/1932 Fischer 156-50O XR cylindrical surface of said second roller that is perpendicular to its axis is parallel to the longitudinal direction; whereby said planar tape is fed between converging and PHILIP DIER, Primary Examiner diverging portions of said insulator from a direction lat- 3,332,825 7/1967 Krylon et a1. 156-436 eral thereto. US. Cl. X.R.

References Cited 1() 185; 29 203; 156500, 517, 244; 264146 UNITED STATES PATENTS 2,204,782 6/1940 Wermine 156244 XR 287,699 10/1883 Meeker 264146XR 

